i

Forest Resources Assessment Working Paper 163

CASE STUDIES ON MEASURING AND ASSESSING

FOREST DEGRADATION

FOREST DEGRADATION IN NEPAL:

REVIEW OF DATA AND METHODS

K. P. ACHARYA

R.B. DANGI

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Sustainably managed forests have multiple environmental and socio-economic functions which are important

at the global, national and local scales, and they play a vital part in sustainable development. Reliable and up-

to-date information on the state of forest resources - not only on area and area change, but also on such

variables as growing stock, wood and non-wood products, carbon, protected areas, use of forests for

recreation and other services, biological diversity and forests’ contribution to national economies - is crucial

to support decision-making for policies and programmes in forestry and sustainable development at all

levels.

Under the umbrella of the Global Forest Resources Assessment 2010 (FRA 2010) and together with

members of the Collaborative Partnership on Forests (CPF) and other partners, FAO has initiated a special

study to identify the elements of forest degradation and the best practices for assessing them. The objectives

of the initiative are to help strengthen the capacity of countries to assess, monitor and report on forest

degradation by:

� Identifying specific elements and indicators of forest degradation and degraded forests;

� Classifying elements and harmonizing definitions;

� Identifying and describing existing and promising assessment methodologies;

� Developing assessment tools and guidelines

Expected outcomes and benefits of the initiative include:

� Better understanding of the concept and components of forest degradation;

� An analysis of definitions of forest degradation and associated terms;

� Guidelines and effective, cost-efficient tools and techniques to help assess and monitor forest

degradation; and

� Enhanced ability to meet current and future reporting requirements on forest degradation.

The Global Forest Resources Assessment programme is coordinated by the Forestry Department at FAO

headquarters in Rome. The contact person is:

Mette Løyche Wilkie

Senior Forestry Officer

FAO Forestry Department

Viale delle Terme di Caracalla

Rome 00153, Italy

E-mail: Mette.LoycheWilkie@fao.org

Readers can also use the following e-mail address: fra@fao.org

More information on the Global Forest Resources Assessment programme can be found at:

www.fao.org/forestry/fra

The coordinators of this work would like to acknowledge the financial contributions made by the

Governments of Finland and Norway and by FAO, the GEF BIP programme and ITTO.

DISCLAIMER

The Forest Resources Assessment (FRA) Working Paper Series is designed to reflect the activities and

progress of the FRA Programme of FAO. Working Papers are not authoritative information sources – they

do not reflect the official position of FAO and should not be used for official purposes. Please refer to the

FAO forestry website (www.fao.org/forestry ) for access to official information.

The FRA Working Paper Series provides an important forum for the rapid release of information related to

the FRA programme. Should users find any errors in the documents or would like to provide comments for

improving their quality they should contact fra@fao.org.

iii

Forestry Department Food and Agriculture Organization of the United Nations

Forest Resources Assessment Working Paper

Case Studies on Measuring and Assessing

Forest Degradation

Forest Degradation in Nepal:

Review of Data and Methods

K. P. Acharya

R.B. Dangi

December, 2009

________________________________________________________________ Forest Resources Assessment Programme Working Paper 163

Rome, Italy, 2009

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v

Abstract

Forests provide a wide range of provisioning, regulating, cultural and supporting services for human

well being collectively known as ecosystem services. The sustainability of forest ecosystems

depends on sustained management, efficient utilization and effective protection measures against

deforestation and forest degradation. Present global discussions on forest degradation have been

focused on reduction of emissions from source and removal of enhancement from the sink i.e.

carbon services. In Nepal, the role of other ecosystem services such as water harvesting, soil

conservation, biodiversity conservation are also equally important for sustaining rural livelihoods

and maintaining environmental condition. Hence, it is imperative to develop common understanding

on forest degradation among the forest users, professionals, policy makers, and the politicians. This

will be helpful developing appropriate public policy to address the problem of forest degradation.

This paper aims to review the past forest resource assessments, methodologies and findings on

forest degradation. The study observed that differentiation on forest quality was recognized since

the first forest resources assessment in the early 1960s. Similarly, all forest resource assessments

have identified criteria and indicators for capturing forest degradation. Forest degradation has been

understood as reduction in production capacity of commercial timber volume. Change in tree

canopy cover was used as a key criterion in assessments. Degradation was assessed through canopy

closure, tree density, regeneration capacity, stand maturity, lopping, species dominancy, grazing,

and soil surface erosion. Forest with no well defined stems has been defined as a shrub land which

increased at a rate of 5.57 percent per year from 1978/79 to 1994. The assessment methodologies

include field survey, satellite images, aerial photography, ground checks or a combination of these.

Finally the paper concludes by offering potential methods for assessing forest degradation in Nepal.

These assessments focused on investigating the association of canopy cover with the commercial

timber volume. This approach neither recognizes ongoing degradation within the dense canopy

forests nor the under storey degradation. In addition, the trade off of different kinds of ecosystem

services was not considered. The use of satellite images with field survey could be a suitable

approach for assessing forest degradation based on the resultant outcomes of all kinds of forest

ecosystem services. A participatory valuation approach using Ecosystem Service Index (ESI) to

assess forest degradation is recommended rather than accounting of individual services. Finally, the

paper argues that the scale of forest services should be understood comprehensively to prevent the

emergence of new drivers of degradation. Hence, forest degradation should be understood as the

reduction in the capacity of forests to produce ecosystem services.

Keywords: Forest, shrub, degradation, method, ecosystem valuation

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1

1. Introduction

Forests are an integral part of the farming system in Nepal. Farmers must have access to forest

products such as leafy biomass for fodder and animal bedding, fuel wood for energy, and timber for

building and agricultural implements (Mahat, 1987; Gilmour and Fisher, 1991; Malla, 2000). In the

high altitude Jumla area, it was estimated that maintaining of one hectare (ha) of paddy land

requires up to 50 ha of forest and grazing land (Whitemand, 1980). Similarly, for middle hills,

Wyatt-Smith (1982) estimated a requirement of 3.5 ha of forest to maintain one ha of agricultural

land. In the whole country, fuel wood derived from forest constituted 84 percent of the total energy

consumed in 2006/07 (WECS, 2006). Similarly, about 42 percent of the fodder requirement for

livestock production is derived from the forests (WECS, 2006; Pandey, 1982). In addition, a

number of forest resources such as high value medicinal and aromatic plants are facing excessive

and unsustainable harvest pressure and degradation (MoEST, 2008). The forestry sector contributes

9.45 percent from direct products and 27.55 percent including indirect services to the national gross

domestic product. On the other hand, over 28 percent of the country’s land is estimated to be in

degraded condition (DFRS, 2008; MoEST, 2008).

The Ministry of Forests and Soil Conservation, Department of Forest Research and Survey (DFRS)

and Government of Nepal have carried out a number of forest resource assessments since the 1960s.

The resource assessment ranges from national level to community level. These inventories differ in

objectives and methodology. The paper reviewed strategic level forest inventories from Nepal. In

addition, two economic studies in Nepal were evaluated. This paper aims to discuss major findings

of different methodologies used and to offer a potential approach that could be utilised for assessing

forest degradation.

The next part of this section presents a brief review on the forest assessment studies conducted in

the past indicating linkages with the thematic elements of sustainable forest management. Section 2

begins with an examination of methodologies, criteria and indicators used for assessing forest

degradation. Section 3 focuses on results of different assessments; it describes the advantages and

disadvantages of various methodologies with respect to cost and accuracy of information. The

discussion section highlights the lesson learned in relation to the drivers of degradation and

detectability of the methods used. It further discusses appropriate methods for assessing forest

degradation such as Ecosystem Service Index (ESI). The paper concludes with a recommendation

that forest degradation should be understood as resultant outcomes of the different services

available from the forest.

Forest resource assessment in Nepal

1. Forest Resources Survey Office (FRSO)1963/64

The forest resource survey office conducted the first forest inventory during the period of 1963-67

using 1953-58 and 1963-64 aerial photography. It used visual interpretation of aerial photographs

and mapping combined with field inventory. The land categories include forest, crop, grass, urban,

water, badly eroded and barren lands. The forest land was subdivided into commercial and non-

commercial forest (HMG 1961; 1969; 1973). The inventory was concentrated only on assessing

extent of forest area, growing stock/ha up to 10 cm top diameter. It does not cover high altitude

forests areas.

2

2. Land Resource Mapping Project (LRMP)1978/79

The LRMP was jointly implemented by the Government of Nepal and Kenting Earth Sciences

Limited Canada with financial support from the Government of Canada. The objectives were to

develop appropriate forest land use maps based on forest types, composition, structure and land

degradation status. The project was implemented during 1977 to 1884 (LRMP 1985; 1986). The

forest resource assessment was made through the combined use of aerial photographs (1977-79),

extensive ground truth checks by helicopter, land surveys and topographic maps.

3. Master Plan for the Forestry Sector (MPFS)1986

The Master Plan for the Forestry Sector (MPFS) was implemented by the Ministry of Forests and

Soil Conservation. The data were based on LRMP information and forest inventory data from

Forest Survey and Research Office (MPFS 1989a; MPFS 1989b). The aim was to update resource

information changes that occurred during the intervening period of LRMP.

4. National Forest Inventory (NFI)1994

The National Forest Inventory (NFI) was started in the early 1990s and completed in 1998 with a

base year of 1994. The programme was implemented by the DFRS with support from the

Government of Finland. The NFI used satellite image analysis - Landsat, aerial photographs and

field measurements.

5. Forest Cover Change Analysis of the Terai Districts (DoF) 2005

The study estimated extent of forest cover and annual rate of change of 20 terai districts. It was

commissioned by the Department of Forests. The forest cover change was estimated by analysing

satellite images of different time periods, supported by ground verification (DoF 2005).

6. Economic Valuation of Ecological Goods and Services (ESE) 2005

The study was commissioned by the Ministry of Forests and Soil Conservation, Government of

Nepal. The study estimated the value of goods and services of forest ecosystems representing

different ecological zones and management regimes (MoFSC 2005). However, the study could not

cover all the ecological regions.

7. Contribution of Forestry Sector to Gross Domestic Product in Nepal (GDP) 2008

The DFRS conducted this study to estimate the actual contribution of forestry sector in national

GDP. Both, use and non-use values had been taken in to consideration in estimating the

contribution. The use values include consumptive goods like timber, fuel wood,

grass/fodder/bedding materials, NTFPs, sand and boulders. Similarly, non use value includes

recreation, eco-tourism, soil conservation and green carbon sequestration (DFRS 2008).

Resource Assessment and the thematic elements of Sustainable Forest Management

A summary of major resource assessment studies and their linkages with thematic elements of

Sustainable Forest Management (SFM) is presented in Table 1. The information reveals that not all

elements of SFM were covered in these measurements. The table shows that resource assessments

were focused to investigate extent of forest area and estimation of timber volume. Two recent

economic studies on the valuation of forest services have added carbon, biodiversity and protective

3

function of the forests in assessments. The forest health and vitality has yet to be considered in the

assessment.

Table 1: Strategic level forest assessment in Nepal and SFM linkages

S.N. Study Year Responsible

Organisation SFM thematic

element 1. Forest Resources Survey 1974 FRSO(DFRS) 1, 5

2. Land Resource Mapping Project 1978/79 LRMP/WECS 1, 5

3. Master Plan for the Forestry Sector 1986 MoFSC/DFRS 1, 5, 7

4. National Forest Inventory 1994 DFRS 1, 5

5. Forest Cover Change Analysis of the Terai Districts 2005 DoF 1

6. Economic Valuation of Ecological Goods and

Services

2005 MoFSC 2, 4,5, 6, 7

7. Contribution of Forestry Sector to Gross Domestic

Product in Nepal,

2008 DFRS 2, 4, 5, 6, 7

Thematic elements of sustainable forest management are. 1. Extent of forest resources; 2. Contribution to the Carbon cycle, forests

and climate change; 3. Forest health and vitality; 4. Biological diversity; 5. Productive functions of forests; 6. Protective functions of

forests; and 7. Socio-economic functions of forests. (Source: FAO 2009)

2. Assessment Methodology

Assessment and tools

It is commonly agreed that measuring forest degradation is more complex and difficult than

deforestation (Panta et al., 2008; Lambin, 1999; Souza et al., 2003). Table 2 summarises the criteria

and methods used in defining and assessing forest degradation. The table reveals that all reviewed

assessments have accepted differences in forest quality. The tree canopy stocking level was found to

be the main criterion used in all assessment. Hence, common acceptance on forest degradation of a

forest in these assessments is the reduction in production capacity of timber volume. The stocking

level was linked with forest productivity. Proxies used include canopy closure, number of mature

trees, the number of preferred trees, density, cut stump, growing stock, regeneration capacity, stand

maturity, lopping, species composition, grazing, and soil surface erosion.

The table shows that 10 percent canopy cover was used to distinguish forest and non-forest areas.

However, there was confusion among the definition of forest and shrub land, shrub lands and scrub,

forest and degraded forests. The most commonly used indicators are crown closure and number of

regeneration sized trees per unit areas. In addition, some qualitative indicators such as lopping and

encroachments were considered as a factor for degradation.

Table 2: Review on methodology of forest assessment studies

Study Degradation

criteria

Indicators Methods Procedure

1. FRSO Stocking

class (Crown

cover <10 %

as a non

forest area)

and density

class)

Scrub and

shrub

• Crown closure and number of

reproduction size trees/ha (well

stocked- >70 % and above 799

reproduction size tree/acre,

Medium 40-69% or 400-699

reproduction size tree/acre; 10-

39 % or 100-399 reproduction

size tree/acre)

• Lands with unmerchantable

tree and shrub species growing

in bush-like clumps.

• Means estimator

• Visual

interpretation of

aerial photographs

• 1:12,000 to

1:60,000 aerial

photographs

• Dot counting

• Area rectification

and adjustment

• Field inventory in

• 1”= 1 mile land use map prepared

using aerial photographs,

• Physiographic regions divided

• Forest, Cropland, Grass, Urban,

Water, Badly eroded and Barren

• Forest subdivided into

commercial/non commercial forest

• Area rectification

• Forest mapping 3”=1 mile

Forest inventory for volume and

growth information

4

Encroached

forest

• Heavy and repeated fuel wood

cuttings

• Lands 10 % or more covered

by tree crown and containing

commercial timbers but

currently being cultivated,

unlikely to remain as forests

• No legitimate ownership

commercial forest

• Systematic grid of 3.2 km x 16.1 km

• Cluster of 5, 800 m² rectangular plot

• Stumps recorded with species & size

• Location of measured trees mapped

• 5 circular sub-plots of 5.27 ft radius

used to record reproduction and

dominant crown cover.

• Conifer growth estimated by borings

2. LRMP Stand

stocking

Soil surface

erosion

• Crown density is % of ground

area covered by tree crowns as

viewed on the photograph or

from air (Crown density < 10

% as non-forest, crown cover

<40 % with an average of

25%)

• Few scattered trees

• Grazing -number of livestock

• Forest fire

• Visual

interpretation of

aerial photographs

(black and white

1: 20,000 to

1:50,000)

• Ground truth

checks by

helicopter

• Land surveys

• Topographic maps

• Land utilisation classification in 4

physiographic regions

• Aerial and ground reconnaissance

• Forest reconnaissance, ground check

• Forest, cultivated, grass lands, shrub

lands and other lands,

• Forest classification

• Interpretation and typing

• Topographic maps and transferring,

• Field work and data collection

• Drafting, planimetry & compilation

3. MPFS Crown

closure

Regeneration

• 10 to 40 % under stocking or

degraded

• 10 to 40 % crown closure or, if

immature containing 250 to

999 regeneration sized trees/ha

• If immature containing 999 or

less regeneration sized trees/ha

• Stands with mature or over

mature trees

• Desk review

• Visual

interpretation of

aerial photographs

and field

verification

• Creation of data base from LRMP

and FSRO research plots, five

physiographic regions

• Field verification using aerial

photographs

• Modelling to update information

4. NFI Crown cover

- stand

density

• <10% crown cover or well

defined stems not found

• Satellite images,

GIS, topographic

maps, vector data-

boundary

• Ground based

inventory

• Visual

interpretation of

aerial photographs

of scale 1:50,000

• Land use categories, forest & shrub

• Forest area into reachable, non

-reachable and encroached, field

verification, data transfer manually

onto planimetric sheets, digitisation

• Development regions separation

• Satellite image analysis - Landsat

TM, NDVI used

District Forest, Churiya forest and

remaining hills districts inventory

• Photo point sampling, two stage

cluster designing, 4x4 km, manual

transfer, stereoscope for land use

5. DoF Crown cover

• Degraded forest means

sparsely distributed trees or

forest land with < 10 % crown

cover including shrub

• GIS, Satellite

images analysis

and ground

verification

• Satellite image analysis and field

verification

• Landsat TM 1990/91 and 2000/01

• Districts level outputs

6. ESE Crown cover

Use value of

ecosystem

services

• <10 % crown cover as

degraded forest or shrub land

• Forest inventory

• Questionnaires

• Market price

• Market price of

substitutes

• Benefits transfer

• Total net stock

• Terai, siwaliks and middle hills

regions in 12 districts covering Sal,

Terai hardwood, Pine, Sub-temperate

forest and shrub land.

• Community forests, protected area

system and government managed

regimes surveyed

7. GDP Crown cover

• <10 % crown cover and shrub

as degraded forest

• Ground based

forest inventory

• Questionnaire

• Market price

• Market price of

substitutes

• Benefits transfer

• Total net stock

• High-Hills, Mid-Hills & Terai regions

• Sal, Terai Mixed Hardwood, Khair/

Sissoo, Lower Slope Mixed

Hardwood, Chir pine, Upper Slope

Mixed Hardwood, Oak /

Castanopsis and others forest types,

• Management regimes – Leasehold,

Government managed, Religious,

Community & protected areas.

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3. Results

Table 3 highlights the extent of forest and shrub categories while more details are presented in

Annex 1. The FRSO survey recognised the forest quality differentiation primarily based on stand

size, density classes, crown closure, merchantable volume, although, there is no clear definition and

assessment of forest degradation. It was characterised by fewer number of trees, lopped trees,

unwanted species (i.e. not commercial tree species), heavy grazing pressure, unpalatable species,

and bushy species. However, it has identified encroached forest as a kind of degraded forest.

Table 3: Extent of forest and shrub land cover in Nepal

Table 4: Estimation of forest degradation rate in terms of increase in shrub land

Shrub land Study Year

Area 000 ha %

Forest degradation % per year

(1978/79 to 1994)

LRMP 1978/79 689 4.7

NFI 1994 1,560 10.6

5.57

Tables 3 and 4 revealed that the total forest area has not changed very much, although the forest

cover has been degrading. Table 3 shows that shrub was not included as a separate land use

category until LRMP, since then it is one of the important land use categories. From the definition

of shrub land (DFRS, 1999) and the above tables, it is clear that shrub lands are those forest areas

from where tree stems were removed but the area still meets other criteria of forests such as canopy

closure. It leads to a conclusion that shrub land is an outcome of forest degradation or is a kind of

degraded forest. The forest and shrub area analysis (DFRS, 1999) result is presented in Box 1.

Box 1: Forest and shrub area results

• Forest covers 29 % and shrub covers 10.6%, both forest and shrub together cover 39.6%.

• In Terai plains, forest area has decreased at annual rate of 1.3% from 1978/79 to 1990/91.

• In the Hilly Area, forest area has decreased at an annual rate of 2.3% from 1978/79 to 1994, whereas

forest and shrub together have decreased at annual rate of 0.2%.

• In the whole country, from 1978/79 to 1994, forest area has decreased at an annual rate of 1.7%,

whereas forest and shrub together have decreased at an annual rate of 0.5%.

Box 1 indicates that deforestation and degradation have been understood in terms of forest and

shrub areas. A comparison of NFI with LRMP shows that the area under shrub land increased by

126 percent during 1978/79 to 1994 or at a minimum rate of 5.57 percent per year. However, the

result shows that there is no substantial change in the total of forest and shrub land area. The

degradation estimate does not include the degradation that remains within the forest category i.e.

Forest

Shrub

Forest and Shrub total

Study Year

Area ‘000 ha % Area ‘000 ha % Area ‘000 ha %

1. FSRO 1964 6,402 45.5 - - 6,402 45.5

2. LRMP 1978/79 5,616 38.1 689 4.7 6,285 42.8

3. MPFS 1985/86 5,424 37.4 706 4.8 6,210 42.2

4. NFI 1994 4,268 29 1,560 10.6 5,828 39.6

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above 10 percent crown cover. The DoF (2005) definition on degraded forest also includes shrub

land as a part of degraded forests. Other elements among different inventories are less comparable

due to different definition and coverage.

Degradation assessment methods

The methodologies used in past assessments can be grouped into Aerial Photography, Field Survey,

Satellite Image and Ecosystem Service Valuation. The following table compares the strengths and

weakness among these methodologies and accuracy level. In the table, the analysis indicates that

forest degradation assessment accuracy increases if it is supported by the ground based information.

Table 5: Relevancy of different forest degradation assessment methodologies in Nepal (Based on

Photographs 1:12,000 to 1: 60,000 and Landsat TM images experiences) Methodology Advantageous Disadvantageous Accuracy

level

Costs Implications

for Nepal Aerial

photography • Easy to understand to

local community

• Visible to

demonstrate forest

degradation such as

crown cover change,

shifting cultivation,

forest fragmentation

• Long experience

• Infrastructure exits

• Require low input on

technology

• Difficulty in mountain area

• High costs,

• High time requirement,

• Nearly abandoned and

replaced by new technologies.

• No latest aerial photographs

available

• Degradation elements such

as grazing, fire damage, forest

NTFPs and understorey

damage, encroachment is not

completely detectable

High High No recent aerial

photographs

available - less

useful

Field survey • Data available for

comparison

• More accurate,

• Widely understood,

• Cheap labour

• Considerable

experience

• Simple technology

• Capture all kinds of

ecosystem services

• National to local scale

possible

• Scattered case study

and academic, research

data available

• More resources,

• Long time requirement

• Difficult in mountain

terrain

• No recent data available

High

(Std. Error

for the top 4

“volume

ranged from

2.61% to

6.66 %).

Medium Considerable

experience

exists, labour is

cheap- still a

good option,

community

involvement is

available,

proposed

FINNIDA

assistance

survey will

generate new

data

Satellite image

analysis and

GIS

• Global uniformity

• Rapidly advancing

technology

• Easy interpretation in

high resolution images

• High resolution

images usable as a map

for demonstration

• Requires low forest

inventory

• Technical capacity and

infrastructure demanding,

• Cloud, shadow and slope in

hilly areas,

• Few control plots for ground

verification,

• Seasonal images

availability,

• Limited data to replace

ground inventory

• Difficult to assess under

storey including NTFPs.

Medium to

high

(67 to 98%

to

distinguish

in different

stocking

class)

Free to

moderately

expensive

(Landsat

to

IKONOS)

Low or

medium

Difficult terrains

support it. Needs

capacity

development, if

combined with

field survey, is

one of the best

option

Ecosystem

service

valuation

• Recognizes broader

value of forest

ecosystem

• Technically demanding

• Outside forestry discipline

Medium to

High

Low to

Moderate

Community

participation,

true valuation of

forest services.

7

4. Discussion

Nepal has a substantial experience on ground based forest inventory which has established

considerable data sources. However, inventories seem to be focused to investigate commercial

timber volume of the forest and not designed for forest degradation assessment in particular.

Further, compared with forest inventory, recent economic studies are much wider, incorporating

concepts of ecosystem services. The average rate of forest conversion to shrub land (5.57

percent/year) is significantly higher than deforestation (1.7 percent/year) for the same period of

1978/79 to 1994. It indicates that the forest degradation is more important for countries like Nepal

for carbon emission or ecosystem services accounting. Although the factors responsible for forest

degradation in Nepal are not clearly understood, a list of possible factors and their detectability is

presented in Table 6.

The most commonly used methods are ground based forest inventory, aerial photography, and

satellite image analysis and a combination of these. Crown cover is taken as a proxy of degradation,

which is unable to address forest degradation until it remains as forest or in under storey. Canopy

reduction will reduce biomass but may enhance watershed conservation and carbon removal or

biodiversity. Table 6 shows that under storey loss is also a fundamental way of forest degradation.

Crown cover base assessment alone is unable to account for many of the drivers of degradation.

Similarly, the table reveals that, field survey combined with image analysis will be able to capture

the key degradation elements and their consequences.

The NFI defined shrubland as an area the same as forests but well-defined stems cannot be found.

By contrast the DoF study defined degraded forest to mean sparsely distributed trees or forest land

with less than 10 percent crown cover including shrub. These definitions indicate that shrub land is

a degraded forest. However, in some cases, these studies have used different definition of degraded

forests and shrub lands, creating confusion. Fuzzy boundaries between land cover categories need to

be removed by providing clear, simple and consistent definition for all assessments.

Table 6: Drivers of degradation and detectability of different methods

Detectability (low to high, 1 - 3) Drivers of degradation Level of

significance

Key degradation element

Field

survey

Aerial

Photographs

Images

Fuel wood removal High Biomass, understorey 3 2 1

Timber removal High Crown cover, biomass 3 2 1

Fodder, leaf litter removal High Biomass, understorey 3 2 1

Over extraction of medicinal

& other species

High Understorey, biomass, biodiversity 3 1 1

Encroachment High Crown cover, habitat, biomass,

understorey

3 2 2

Overgrazing High Understorey, soil, habitat 3 1 1

Development activities- Road High Crown cover, habitat, biomass,

fragmentation

3 3 2

Wild fire Medium Understorey, biomass, soil,

biodiversity

2 1 2

Settlements to landless Medium Crown cover, habitat, biomass 3 2 2

Invasive species Low Biomass, understorey, habitat,

biodiversity

3 1 1

Rot disease Low Biomass 3 1 1

Floods Medium Biomass, understorey, biodiversity 2 1 2

Wind throw Low Biomass, species 3 2 2

8

Past assessments have done spatial and temporal mapping of forest conditions of Nepal which

suggest that forest degradation is causing changes in the forest structure, composition, stocking and

forest types, change of the vertical structure or alteration of other attributes. Sharma and Suoheimo

(1995) found that about 45 percent of trees are affected by the rot diseases in Makawanpur and

Rautahat districts. Similarly, Acharya (2000) stated that there is degradation on existing forest stock

due to repeated logging practices resulting in lower quality forest types. It was illustrated through

conversion of Sal forest (>60 percent of basal area) to Sal Terai Hardwood and finally to Terai

Hardwood (sal basal area <20 percent).

Nepal is suffering acutely from different sources of forest degradation. Forest encroachment is a

serious problem in the Terai plains. An estimate shows that 100,000 ha of forest is under

encroachment in the Terai and many more coming under threat of encroachment by illegal

squatters. High altitude forests are degraded due to the stocking of livestock units 9 times higher

than their carrying capacities (MoEST, 2008; NBS, 2002). Table 6 illustrates that degradation can

be the result of a single factor or a combination of multiple factors. It is highly significant for

maintaining subsistence economy which is based on the exploitation of natural resources as a major

source of livelihoods. The detection of such drivers is extremely limited with remote sensing unless

it reaches to serious level or it is supported by ground based information. Any methodological

innovations should consider the ground reality. Forest degradation may occur in following ways:

1. Reduction in biophysical attributes of forests such as crown cover in such a way that forest

remains as forest, up to10 percent.

2. Reduction of crown cover from shrub land or degraded forest until it is converted to other land

use. It has implications for services including carbon sequestration.

3. National area statistics will show both 1 and 2 on forest or shrub/degraded forest category

undermining the degradation.

4. Degradation may occur in under storey canopy due to removal of NTFPs and other resources.

The proposed field based inventory, with the assistance from the Government of Finland, will

generate substantial spatial and temporal information in Nepal. In addition, regional cooperation

through South Asian Association for Regional Cooperation (SAARC) could be a very practical

solution for such assessment specifically for small developing countries such as Nepal.

There is a need for the development of a comprehensive methodology to understand and value

forest degradation from ecosystem services perspectives. It could be based on the use of satellite

images combined with field survey. In addition, a participatory ecosystem services valuation

approach (PESVA) is recommended for understanding ecosystem services comprehensively to

capture degradation factor as shown in Table 6. This is simple but manageable by community

institutions for community forest management and will clearly help understanding forest

degradation. The PESVA requires expert inputs on the methodological template development, index

development, default value; key and simple procedure. In addition, satellite images supported by

ground observations could be the most efficient way to estimate rates of forest degradation by

locations to know where and how forests are being degraded.

The conceptual clarity on issues such as what is forest degradation, its impacts on ecosystem

services, fragmentation, local drivers of degradation, and opportunity costs is essential. The use of

satellite images and field based inventory requires additional capacity development, data sharing

mechanisms, permanent field plots, biomass studies, NTFPs and wildlife inventory. Likewise,

9

research to assess under storey vegetation in different conditions using images needs special

consideration.

4. Conclusions

Forest degradation is a unique process affecting forest ecosystem services (MEA, 2005). These

drivers are different in across and within the countries. A detailed and more specific understanding

of these drivers is necessary to address forest degradation. There is a need for a comprehensive

methodology to understand and value forest degradation from ecosystem services perspectives for

subsistence economy, poor people and forest dwellers depending on ecosystem services for daily

needs.

Nepal has a substantial experience on ground based forest inventory which has established

considerable data sources on forest stock. The methods used are aerial photographs, field inventory

and satellite images analysis. The further development of methodologies in assessing degradation

will largely depend on definitions. Different organizations have used different definitions and a

consensus definition is needed. Similarly, the clear distinction between shrub land and degraded

forest and methods to assess shrub lands are required. Similarly, several policy documents have

used forest degradation differently, which needs to be resolved. It should consider full ranges of

biophysical and socio-economic conditions. Nevertheless, in Nepal, a robust methodology which

can capture a range of drivers causing forest degradation (Table 6) is necessary. The present

methodologies can be improved in two ways. First, the use of satellite images supported by ground

based inventory. It should cover major forest types, physiographic regions and management

regimes. The use of satellite images and field based inventory is suitable to assess biomass, growing

stock, basal area, species composition, structure and forest type related assessment. This approach

will combine the strengths of both methods.

A second approach would be PESVA which will be based on the concept of forest ecosystem

services index (ESI). The ESI approach should consider use value (UV) concept instead of total

economic value (TEV). It should consider direct use value (DUV) and indirect use value (IUV)

concept, which have more critical influence on forest degradation. ESI is sum of different

components of ecosystem service indexes. For a particular forest, it may ranges from 0 to 1.

Periodic monitoring and comparison of indexes with base line index (Box 2) will provide

information about the extent of forest degradation or enhancement.

However, there is a need for capacity development, data base management system at national and

local levels. Pilot studies are required to test and generate more information on forest degradation.

Such evidence will have positive influence in national resources allocation for forest management.

Box 2: Ecosystem Service Index (ESI) ESI is a summary index of ecosystem services of a forest. It measures the average performances of use

values of the forest. It is estimated against ecosystem services as defined by MEA. Some of the indicators for

discussion could be as follows:

• Services-trend index: it is estimated by total number of ecosystem services of the forest, number of

services in increasing trend, number of services in decreasing trend

• Service-value index: it is estimated by optimum values for a given type of forest, value presently

provided by the forest.

10

The better understandings of forest degradation needs commitments at political and bureaucratic

level, infrastructure, legal measures of forest monitoring and national strategy, coordination of

agencies using remote sensing data, understanding diverse nature of local drivers of degradation and

measurement and opportunity cost. Similarly, there is a strong need for establishing an effective

degradation monitoring system.

Nepal can move ahead with the development of guidelines for forest monitoring, clear definition,

procedure for consistency, piloting covering major ecological zones and forest types, and

management regimes. Regional cooperation with India through SAARC could be a practical option

for cost effective assessment of forest degradation and its periodic monitoring every five years.

Nepal may request for remote sensing data from India and produce a periodic report based on

ground inventory by DFRS. PESVA needs additional exercises on creating default values developed

through available information and expert consultation. A programme framework that can be applied

at community level, especially in Nepal, where communities are managing forests is essential. It

also needs the development of simple format, guidelines and procedures. The paper concludes that

isolated approaches such as carbon sequestration to perceive forest degradation will create new

problems or drivers of forest degradation. Therefore, this paper concludes that forest degradation is

the reduction in ecosystem services capacity of forest.

Figure: Foresters undertaking a ground based inventory. (Source: WWF, Nepal)

11

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Forest Research and Survey, Kathmandu, Nepal.

DFRS, 1999. Forest Resources of Nepal, Department of Forest Research and Survey, Publication no

74. Kathmandu, Nepal.

DoF, 2005. Forest Cover Change Analysis of the Terai districts (1990/91-2000/01. Department of

Forest, Kathmandu, Nepal.

FAO, 2009. Terms of Reference for the Preparation of Case Studies on Forest Degradation.

Gilmour, D.A. and Fisher, R..J. 1991. Villagers, Forest and Foresters: the Philosophy, Process and

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Region. Forest Resources Survey, Department of Forestry, Nepal.

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methodological issues. Global Ecology and Biogeography 8: 191-198.

LRMP, 1985. Land Utilization Report, HMG/Kenting Earth Science Limited.

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Malla, Y.B. 2000. Impacts of Community Forestry Policy in Rural Livelihoods and Food Security

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Conservation, Kathmandu, Nepal.

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Nepal.

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13

Annex 1: Findings of the past assessments in Nepal

Study Key findings related to forest degradation Inferences 1. FRSO

Area

45.5 % of land covered by forest, out of which 47 % is

commercial. Whereas in hills 58.1 % forest lands, commercial

forest area in the hill 34.4 %

Composition

Sal covers 20.7%, sawn timber stands 77 % and 23 %

pole/sapling/regeneration stand

Stocking

Average volume 63 m3/ha. In Hills, 35.1 % of commercial

forest is well stocked, 28.5 % medium and 8.7 % is poorly

stocked, over storey poor with understory medium 7.6,

overstorey poor understory well stocked well stocked 3.3% and

overstorey medium with understory well stocked 16.8 %

Tree distribution

In hills, 47 % of tree below 22 inch diameter class are from

undesirable species (not used for industrial wood, desirable

species are sal, Asna, Khair, Chirpine, Blue Pine, Spruce, Fir

and Hemlock)

Non commercial forest

In hills, encroachment: 0.06 percent of non commercial forest

area (5,236 acre); Scrub and shrub: 5.28 % (797,203 acre)

Focus was on total merchantable

volume of selected species in

commercial forest area.

Forest encroachment was

recognised due to fuelwood

extraction and lopping.

2. LRMP Area Forest area 5,616,800 ha (38.01 %), shrub 689,900 ha

(4.68 %), >40 % crown cover is 28.1%,

Stocking 34% (excluding High Himal) of forest is under stocked

degraded forests; 55% of forest is in very poor condition in

middle mountains;

Forest areas are converting into

degraded forest-shrub.

3. MPFS Area Forest 37.4 %, Shrublands and degraded forests: 5 % (706,000

ha) P 24, MPFS

Composition

59 % hardwoods, 17 % conifers and 24 % mixed forests. Pole

reproduction size constitutes only 1% of volume/ha, whereas

small timber 65.2% and remaining 1/3rd

by large timber.

Stocking and Degraded forest

Only 15% of forest area has >70 % crown cover, <40 % crown

cover is in 26.3% of the total forest, 59% have 40-70%. Per ha

growing stock is 96 m3 whereas total forest biomass is 628

million ton.

Shrublands increased due to

over cut for fuel wood and

lopping for fodder.

Other causes of degradation are

fire, cross border timber

smuggling, almost 60% shrub

lands are in middle mountains.

Rate of conversion of forest area

into degraded forest/shrub not

reduced.

Some of deforested area remains

as degraded forests.

4. NFI Area Forest 29 % (4,268,800), shrub 10.6 % (1,559,200 ha), In terai,

forest has decreased at annual rate of 1.3% from 1978/79 to

1990/91. In the hilly area, forest area has decreased at an annual

rate of 2.3 % from 1978/79 to 1994, whereas forest and shrub

together have decreased t an annual rate of 0.2%. In the whole

country, from 1978/79 to 1994, forest area has decreased at an

annual rate of 1.7 %, whereas forest and shrub together have

decrease at an annual rate of 0.5%.

Composition

28.2 % of total stem volume is occupied by sal followed by

Quercus – 9.3 %. All together 229 species identified in

inventory.

Stocking

Mean stem volume is 178m3/ha in 408 stem/ha bigger than 10

Rate of conversion of forest area

into degraded forest-shrub is

significantly increased. There is

higher degradation rate in hilly

region whereas deforestation is

prominent in the terai.

Forest degradation rate is double

than the deforestation rate for

1978/79 to 1994. (Degradation

is 3.5 % per year compared to

1.7 % per year of deforestation)

NFI assumed no shrubland in

terai, would have been higher

rate of degradation. Please refer

to DoF study.

14

cm dbh. Total stem volume of reachable forest is 387.5 million

m3 and biomass is 428.5 million ton

Non reachable forest About 51.5 % of the forests of Nepal are reachable.

Forest degradation

The shrub land area is result of forest degradation, which has

increased from 689,900 ha in 1978/79 LRMP estimates to

1,559,200 ha in NFI. It is an increase of 869,300 ha in 16 years

at a rate of 56 % or at an annual rate of 3.5 %. The degradation

within the forest category is not accounted in the estimate.

5. DoF Total forest area in 20 terai districts is 1,149,494 ha (excluding

protected area). Out of the total, 88 % (1,011,362 ha) is forest

and 12 % (138,132) is degraded forest.

Decreasing trend in land cover

change in erai plains during

1990/91 to 2000/01.

Encroachment has profound

effects on forest decline.

6. ESE The highest absolute value per ha was found in the Sal forest

(Nrs 3 million).

Within the Terai forest ecosystems, the absolute value of shrub

land (Nrs 0.76million is half than Terai Mixed Hardwood Forest

(Nrs 1.5 million).

The shrub lands have lower per ha values compared to forests

ecosystems in respected region.

Pine forest has lowest values within the forest ecosystems.

There is variation in TUV per ha in six research sites. It is

mainly due to variation in existing stock of the forest.

The ecosystem services vary

accordingly land use,

physiographic regions and forest

types.

Values of all three terai

ecosystems are higher than hills

Forest ecosystem services can

be valued by use value of the

ecosystem services

7. GDP Forestry sector contribution to GDP in the past was generally

estimated 4.4% compared to 9.45%, whereas it is 27.55%

including intangible benefits.

Forests contribute significantly

on national gross production.

Indirect use value of forest

ecosystem must be valued to

realise forest benefits.